Telepresence systems allow a user at one location to view a remote location (e.g., a conference room) as if they were present at the remote location. Mutually-immersive telepresence system environments allow the user to interact with individuals present at the remote location. In a mutually-immersive environment, the user occupies a display booth, which includes a projection surface that typically surrounds the user. Cameras are positioned about the display booth to collect images of the user. Live color images of the user are acquired by the cameras and subsequently transmitted to the remote location, concurrent with projection of live video from the remote location on the projection surface surrounding the user.
Ideally, the mutually immersive telepresence system would provide an audio-visual experience for both the user and remote participants that is as close to that of the user being present in the remote location as possible. This presents several conflicting requirements for the display apparatus.
The display booth surrounds the user with visual stimuli from the remote location. Typically, though, a view of the ceiling of the remote location is not reproduced for the user. This is because a view of the ceiling of the remote location conveys little relevant information for the user and people rarely look overhead when meeting with others. Since most indoor light comes from above, not recreating the ceiling of the remote location in the display booth results in a top of the user's head appearing unnaturally dark in the video of the user displayed at the remote location. Lighting the top of the user's head presents a challenge in that lighting the user's head will also wash out the projection of the remote location being viewed by the user.
The display booth ideally creates a sound field for the user which accurately recreates sound from the remote location. An ideal auditory environment would be completely dead, with no reflected sound, so that the ambiance of the remote location would be created by playing sound acquired at the remote location. However, the projection surface which surrounds the user will strongly resonate at a characteristic frequency and will be a very “live” environment (i.e., reflecting most of the sound energy output from the speakers). The resonance manifests as ringing (e.g., like standing inside a bell) and is characterized by a large reverberation time constant.
What is needed is an accessible display booth for an immersive telepresence system which is characterized by a shorter reverberation time constant.